// Copyright 2007, 2008, 2009, 2011 The Apache Software Foundation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package org.hxzon.tapestry5.components;

import java.util.List;

import org.apache.tapestry5.Asset;
import org.apache.tapestry5.Block;
import org.apache.tapestry5.ComponentParameterConstants;
import org.apache.tapestry5.ComponentResources;
import org.apache.tapestry5.PropertyOverrides;
import org.apache.tapestry5.annotations.Component;
import org.apache.tapestry5.annotations.Events;
import org.apache.tapestry5.annotations.Parameter;
import org.apache.tapestry5.annotations.Path;
import org.apache.tapestry5.annotations.Property;
import org.apache.tapestry5.annotations.SupportsInformalParameters;
import org.apache.tapestry5.beaneditor.PropertyModel;
import org.apache.tapestry5.corelib.components.EventLink;
import org.apache.tapestry5.grid.ColumnSort;
import org.apache.tapestry5.grid.GridConstants;
import org.apache.tapestry5.grid.GridModel;
import org.apache.tapestry5.grid.GridSortModel;
import org.apache.tapestry5.internal.InternalConstants;
import org.apache.tapestry5.internal.TapestryInternalUtils;
import org.apache.tapestry5.ioc.Messages;
import org.apache.tapestry5.ioc.annotations.Inject;
import org.apache.tapestry5.ioc.internal.util.CollectionFactory;
import org.hxzon.tapestry5.util.TapestryEx;

/**
 * Renders out the column headers for the grid, including links (where appropriate) to control column sorting.
 * 
 * @tapestrydoc
 */
@SupportsInformalParameters
@Events(InternalConstants.GRID_INPLACE_UPDATE + " (internal event)")
public class GridExColumns {
    /**
     * The object that provides access to bean and data models, which is typically the enclosing Grid component.
     */
    @Parameter(value = "componentResources.container")
    private GridModel gridModel;

    /**
     * Optional output parameter that stores the current column index.
     */
    @Parameter
    @Property
    private int index;

    /**
     * If true, then the CSS class on each &lt;TH&gt; element will be omitted, which can reduce the amount of output
     * from the component overall by a considerable amount. Leave this as false, the default, when you are leveraging
     * the CSS to customize the look and feel of particular columns.
     */
    @Parameter
    private boolean lean;

    /**
     * Where to look for informal parameter Blocks used to override column headers.  The default is to look for such
     * overrides in the GridColumns component itself, but this is usually overridden.
     */
    @Parameter(value = "this")
    private PropertyOverrides overrides;

    /**
     * If not null, then each link is output as a link to update the specified zone.
     */
    @Parameter
    private String zone;

    @Component(parameters = { "event=sort", "disabled=sortDisabled", "context=columnContext", "class=sortLinkClass", "zone=inherit:zone" })
    private EventLink sort, sort2;

    @Inject
    @Path("${" + ComponentParameterConstants.GRIDCOLUMNS_ASCENDING_ASSET + "}")
    private Asset ascendingAsset;

    @Inject
    @Path("${" + ComponentParameterConstants.GRIDCOLUMNS_DESCENDING_ASSET + "}")
    private Asset descendingAsset;

    @Inject
    @Path("${" + ComponentParameterConstants.GRIDCOLUMNS_SORTABLE_ASSET + "}")
    private Asset sortableAsset;

    @Inject
    private Messages messages;

    @Inject
    private Block standardHeader;

    /**
     * Caches the index of the last column.
     */
    private int lastColumnIndex;

    @Property(write = false)
    private PropertyModel columnModel;

    @Inject
    private ComponentResources resources;

    void setupRender() {
        lastColumnIndex = gridModel.getDataModel().getPropertyNames().size() - 1;
    }

    public boolean isSortDisabled() {
        return !columnModel.isSortable();
    }

    public String getSortLinkClass() {
        switch (getSortForColumn()) {
        case ASCENDING:
            return GridConstants.SORT_ASCENDING_CLASS;

        case DESCENDING:
            return GridConstants.SORT_DESCENDING_CLASS;

        default:
            return null;
        }
    }

    private ColumnSort getSortForColumn() {
        GridSortModel sortModel = gridModel.getSortModel();

        String columnId = columnModel.getId();

        return sortModel.getColumnSort(columnId);
    }

    public String getHeaderClass() {
        List<String> classes = CollectionFactory.newList();

        if (!lean) {
            classes.add(columnModel.getId());
        }
        String sort = getSortLinkClass();

        if (sort != null) {
            classes.add(sort);
        }
        if (index == 0) {
            classes.add(GridConstants.FIRST_CLASS);
        }
        if (index == lastColumnIndex) {
            classes.add(GridConstants.LAST_CLASS);
        }
        return TapestryInternalUtils.toClassAttributeValue(classes);
    }

    public boolean isActiveSortColumn() {
        return getSortForColumn() != ColumnSort.UNSORTED;
    }

    /**
     * Normal, non-Ajax event handler.
     */

    void onSort(String columnId) {
        gridModel.getSortModel().updateSort(columnId);
    }

    /**
     * Ajax event handler, which carries the zone id.
     */
    boolean onSort(String columnId, String zone) {
        onSort(columnId);

        resources.triggerEvent(TapestryEx.Event_GridInplaceUpdate, new Object[] { zone }, null);

        // Event is handled, don't trigger further event handler methods.

        return true;
    }

    public Asset getIcon() {
        switch (getSortForColumn()) {
        case ASCENDING:
            return ascendingAsset;

        case DESCENDING:
            return descendingAsset;

        default:
            return sortableAsset;
        }
    }

    public Object getColumnContext() {
        if (zone == null) {
            return columnModel.getId();
        }
        return new Object[] { columnModel.getId(), zone };
    }

    public String getIconLabel() {
        switch (getSortForColumn()) {
        case ASCENDING:
            return messages.get("ascending");
        case DESCENDING:
            return messages.get("descending");
        default:
            return messages.get("sortable");
        }
    }

    @SuppressWarnings("unchecked")
    public List<String> getColumnNames() {
        return gridModel.getDataModel().getPropertyNames();
    }

    public void setColumnName(String columnName) {
        columnModel = gridModel.getDataModel().get(columnName);
    }

    public Block getBlockForColumn() {
        Block override = overrides.getOverrideBlock(columnModel.getId() + "Header");

        if (override != null) {
            return override;
        }
        return standardHeader;
    }
}
